Novartis AG said on Thursday it would sell its nearly one-third voting stake in Roche back to its cross-town rival for $20.7 billion, disentangling the two competitors that had been linked by the investment for more than two decades.

The deal extricates Roche from ownership ties to a major rival with strategic vetoing power, though it has however kept a passive role in the face of powerful Roche family shareholders.

The transaction sent Roche shares to a record high. By mid-morning, they were up 2.4%, while Novartis shares were up 0.2%.

Novartis has agreed to sell 53.3 million Roche bearer shares for $388.99 (356.93 Swiss francs) per share, a price that reflects the volume-weighted average of the Roche non-voting equity certificates over the 20 trading days to Nov. 2, Novartis said in a statement.

In a separate statement, Roche said it will use debt to finance what it called a “disentanglement of two competitors” and plans to reduce its capital by cancelling the repurchased shares to regain full strategic flexibility.

Novartis’ involvement started in 2001, when Swiss activist investor Martin Ebner, known for orchestrating the merger that created banking giant UBS, offered his Roche stake to its cross-town rival out of frustration over rebuffed proposals.

Ebner at the time had amassed the holding in Roche to push for strategic change but ran into opposition from the founding families that control the group.

Roche shareholders will vote on the plan at an extraordinary general meeting on Nov 26.